I am new at this but I am trying to get information from more knowledgeable Blazer owners.As you can see my code was [ PO171]System to lean bank one on my 2003 Blazer L/S 4.3 liter.I have added a fuel injector cleaner to a full tank of gas to see if it helps at all.This code just came on this morning and it also says the item at fault is the Engine Control Unit [2 ] anyone out there help me out like I said I am new to this posting but I enjoy working on my own if possible can anyone help me out.And hopefully this is a small module not the cars computer.

 

Perhaps this thread will help you:


https://blazerforum.com/forum/diagno...plained-35154/

 

I took it out for a freeway run after adding the injector cleaner and wile out the check engine light went out and the code reader went from red to yellow what dose this mean.

 

It might tell you in the owners manual for the code reader I would suspect the hard fault is no longer being detected, and the DTC was moved to a pending or history file in the PCM.

 

You know I used to have a smart *** teacher years ago that loved to say RTFB read the f,in book if that fails then ask me.The [3150] code reader don't have a instruction book like the older ones you have to go on line with your code and for $9.95 they will give you the answer to what the problem is but only for a hard code like the PO117 but not the yellow light flashing for a EVAP system still running its test,s on the IM system that is the only reason why I asked.